A 2,3-dihydroimidazo[2,1-b]oxazole compound or salts thereof are useful compounds as an antitubercular agent (WO2004/033463, WO2004/035547 and WO2005/042542), the oxazole compound or salts thereof are represented by the general formula (1):
wherein R1 represents hydrogen or a lower alkyl group;
R2 represents a piperidyl group represented by the general formula (A1):
(wherein R3 represents:(A1a) a phenoxy group having a halogen-substituted lower alkoxy group(s) as a substituent(s) on a phenyl group,(A1b) a phenoxy-substituted lower alkyl group having a halogen-substituted lower alkyl group(s) as a substituent(s) on a phenyl group,(A1c) a phenyl-substituted lower alkoxy lower alkyl group having a halogen(s) as a substituent(s) on a phenyl group,(A1d) a phenyl-substituted lower alkyl group having a halogen-substituted lower alkoxy group(s) as a substituent(s) on a phenyl group,(A1e) an amino group having a phenyl group having a halogen-substituted lower alkoxy group(s) as a substituent(s) on a phenyl group, and a lower alkyl group, or(A1f) a phenyl-substituted lower alkoxy group having a halogen-substituted lower alkoxy group(s) as a substituent(s) on a phenyl group), or a piperazyl group represented by the general formula (A2):
(wherein R4 represents:(A2a) a phenyl-substituted lower alkenyl group having a halogen-substituted lower alkoxy group(s) as a substituent(s) on a phenyl group, or(A2b) a halogen-substituted phenyl group); andn represents an integer of 1 to 6. These Patent Documents disclose, as a manufacturing method of the 2,3-dihydroimidazo[2,1-b]oxazole compound, for example, a method shown by the following Reaction Formula A:
wherein R1, R2 and n are the same as in the above; andX1 represents a halogen atom or a nitro group.
The above-mentioned'oxazole compound is an important compound as antitubercular agent, and the development of alternative methods for manufacturing industrially and profitably the compound is much desired.
It is an object of the present invention to provide a novel intermediate for manufacturing a 2,3-dihydroimidazo[2,1-b]oxazole compound represented by the general formula (1) in a high yield and a high purity, and a manufacturing method of the intermediate.